Students will be doing 2 activities (could be done over 2 days) to explore the factors that affect the solubility of solutes in solvents and the factors that affect the rate of dissolving.
Students should be given this link prior to this class to explore how salts and sugars dissolve in water and allow them to start thinking about solubility and dissolving (or could be done as a class to introduce lesson). Students will be able to return to the above link whenever they wish to review solubility. There are sample questions and suggestions listed for the teacher on the page above.
Students will be introduced to solubility with this activity. Working in groups of 4, students will predict whether the following six solutes: sugar, table salt, paraffin wax, glycerol, iodine and petroleum jelly are soluble in two solvents (water and mineral oil). They will then design an experiment to test their hypotheses and working in groups, they will explain what occurred on a molecular level. Students will present their results for one of the solutes (teacher should assign to students) to the class the next day, in the format of their choice.
Extension: Depending on the readiness of your students, you could challenge them to find a practical application of the solubility of their solute in both polar and non-polar solvents and include this in their presentation to the class.
Activity #2: Factors Affecting Rates of Dissolving
This activity is much simpler and requires less teacher preparation. Group students into small groups (3 or 4). Give each a sugar cube. Ask them to come up with 3 different ways they can increase the rate of dissolving that sugar cube in water (they have to use all the sugar in the cube).
Ask students to come up with a procedure to test how effective each factor that affects the rate of dissolving is and come up with a list of most to least effective factors. Students will get their procedure approved and will test their designed labs. Students can then share results with their classmates and decide overall what is the most and least effective methods to increase the rate of dissolving.
Lab: Creating Solubility Curve of Potassium Nitrate (optional)
This is a classic lab in grade 11 chemistry that allows students to nicely illustrate the relationship between solubility and temperature. A procedure for this lab is found in all chemistry text books.
If desired, teachers may wish to ask students to complete this lab to further examine how temperature affects solubility be creating a solubility curve of KNO3.
Curriculum Expectations:
2.1 Use appropriate terminology related to aqueous solutions and solubility
3.1 Describe the properties of water and explain why these properties make water such a good solvent 3.2 Explain the process of formation for solutions that are produced by dissolving ionic and molecular compounds in water and solutions that are produced by dissolving non-polar solutes in non-polar solvents
3.3 Explain the effects of changes in temperature and pressure on the solubility of solids, liquids and gases
Introduction: Solubility of Salt and Sugar Simulation
http://phet.colorado.edu/en/simulation/sugar-and-salt-solutions
Students should be given this link prior to this class to explore how salts and sugars dissolve in water and allow them to start thinking about solubility and dissolving (or could be done as a class to introduce lesson). Students will be able to return to the above link whenever they wish to review solubility. There are sample questions and suggestions listed for the teacher on the page above.
Activity #1: Factors Affecting Solubility of Solutes in Solvents
Investigating Solutes & Solvents
Students will be introduced to solubility with this activity. Working in groups of 4, students will predict whether the following six solutes: sugar, table salt, paraffin wax, glycerol, iodine and petroleum jelly are soluble in two solvents (water and mineral oil). They will then design an experiment to test their hypotheses and working in groups, they will explain what occurred on a molecular level. Students will present their results for one of the solutes (teacher should assign to students) to the class the next day, in the format of their choice.
Extension: Depending on the readiness of your students, you could challenge them to find a practical application of the solubility of their solute in both polar and non-polar solvents and include this in their presentation to the class.
Activity #2: Factors Affecting Rates of Dissolving
This activity is much simpler and requires less teacher preparation. Group students into small groups (3 or 4). Give each a sugar cube. Ask them to come up with 3 different ways they can increase the rate of dissolving that sugar cube in water (they have to use all the sugar in the cube).
Ask students to come up with a procedure to test how effective each factor that affects the rate of dissolving is and come up with a list of most to least effective factors. Students will get their procedure approved and will test their designed labs. Students can then share results with their classmates and decide overall what is the most and least effective methods to increase the rate of dissolving.
Lab: Creating Solubility Curve of Potassium Nitrate (optional)
This is a classic lab in grade 11 chemistry that allows students to nicely illustrate the relationship between solubility and temperature. A procedure for this lab is found in all chemistry text books.
If desired, teachers may wish to ask students to complete this lab to further examine how temperature affects solubility be creating a solubility curve of KNO3.
Curriculum Expectations:
2.1 Use appropriate terminology related to aqueous solutions and solubility
3.1 Describe the properties of water and explain why these properties make water such a good solvent
3.2 Explain the process of formation for solutions that are produced by dissolving ionic and molecular compounds in water and solutions that are produced by dissolving non-polar solutes in non-polar solvents
3.3 Explain the effects of changes in temperature and pressure on the solubility of solids, liquids and gases